Bird’s Head Seascape – Natural History Notes (PT3: Sinister Hitchhikers)

Bird’s Head Seascape – Natural History Notes (PT3: Sinister Hitchhikers)

Parasites permeate every corner of the animal kingdom; indeed, even parasites have their own parasites. With one of my PhD colleague’s research focusing on coral reef fish parasites I started to pay more attention to these sinister members of the community.  Now I can hardly do a dive without coming across a stricken fish or other reef creature that is suffering at the hands of one of these insidious but fascinating beasts.

Funky Pill Bugs

Sweeper fish with parasite on headSweeper fish with parasite on headIn January this year I was aboard Dewi Nusantara for my charter exploring Raja Ampat’s southern reaches and the island of Kofiau.  As always, I gave lectures about the area’s marine life, so my regular guests are well aware of my penchant for external parasites.  Several even come up from their dives regaling me with stories of how many they’ve seen: there is a funny ecological quirk whereby if one fish is infected often a large proportion of the same species locally also will be.  According to my colleague, this is because these parasites ‘burst’ spawn and their offspring will infect many other individuals around the same area.

Parasites are extremely common on coral reefs.  Some bite and gorge themselves on blood very rapidly then drop off, whilst others grip on their host for their whole adult life.  The external parasites that have been the focus of my natural history notes of late are isopod crustaceans, which are basically marine pill bugs (woodlice for the Brits, or sea lice to anglers), found in the family Cymothoidae.  They are extremely species and site specific, usually found in the exact same location on just one host species.  Some attach themselves externally to scales, others are flesh burrowing (I saw some of these in temperate Australia recently, and they made me feel quite queasy), some attach to the gills and others live in the fish’s mouth.

Not Forgotten

Fusilier with chin parasite. Raja AmpatFusilier with chin parasite. Raja AmpatMost recently, amongst one of the enormous schools of passing fusiliers at the dive site ‘Boo Windows’, something caught my eye under one of the fish’s chins.  When I was able to get a closer look at a cleaning station I saw that the stricken fish had a huge white isopod parasite clutching to the underside of its head.  It had obviously been there sometime, as the fish was slightly deformed where the parasite’s little legs were latched on.  There was even a groove for the parasite to rest.

Whilst many of these copepod parasites are dark in colour, I was interested to see that this one was white.  Fusiliers’ type of colouration is known as countershading, whereby their belly is paler than their dorsal surface.  This helps to camouflage them against predators from above, as their dark top-half acts as camouflage against the darker water below.  Contrastingly, the pale belly camouflages them against predation from below against the predators looking up at the bright sky.  The parasite appears to have followed suit and matches the fish’s paler ventral colours.  Through natural selection, one would assume that fish carrying dark parasites would more likely be eaten than those carrying pale chin parasites.  The pale parasite is less likely to draw the attention of their host’s predators.  Since this would also mean that the parasites too are less likely to be eaten and are thus able to pass on their genes, eventually a pale parasite has prevailed.

I was intrigued to see only one isopod living under the fusilier’s chin, but in one of my images I discovered that there was actually another smaller individual living under the larger one.  The bigger of the two is the female, and the tiny one beneath is the male.  Since he is hidden under the large female’s tail, he is dark grey in colour.  After mating, the eggs of cymothoid isopods develop in a pouch on the female’s body.  There the young hatch and undergo their first moult.  The active and agile young then leave the brood pouch and go in search of a host of their own.  They have well-developed eyes, helping them to track down a host.  Between leaving the mother’s pouch and making permanent attachment on their new host, they undergo several moults.  Each stage is perfectly adapted for the job the larva needs to complete.  Sensory structures come and go and at the last stage grasping claws appear, which help their final attachment to the host.

Shrimp with internal isopod parasite

These isopod parasites are common on the reef and infect many different fishes; however, they are not only limited to fishes.  There are certain species that also inhabit the gill arches of crustaceans.  Whilst they look punishing for the host, parasites generally don’t kill them.  They can cause lesions, reduced their growth rates and make them weak and more prone to illness or predation, but the parasite wouldn’t actually benefit from the host’s demise – they’d lose their home.  Some parasites have extremely sinister tricks up their sleeve to ensure that they alone are looked after.  Certain parasites are able to sterilise their host, so the host producing its own offspring does not waste vital energy.

Next time you are diving in Raja Ampat, I suggest you keep you eyes peeled for these sinister hitchhikers living on the reef’s creatures.  Unsurprisingly, there are more species of these parasites in the Coral Triangle region than anywhere else on Earth.  After all, they too help add to the extraordinary number of species that make coral reefs one of the most biodiverse ecosystems on the planet.

 By Dr Richard Smith | Originally written for Science & Conservation Blog

Links to previous blogs:

PART ONE | In Appreciation of Damsels

PART TWO | Craving Cryptic Crustaceans

PART FOUR | The Pygmy Seahorses of Raja Ampat

PART FIVE | Raja Rarities

Bird’s Head Seascape – Natural History Notes (PT 2: Craving Cryptic Custaceans)

Bird’s Head Seascape – Natural History Notes (PT 2: Craving Cryptic Custaceans)

Raja Ampat is famed for its outstanding fish diversity, so it’s sometimes forgotten that the area’s species richness extends beyond the piscine delights.  Although I would probably count fishes as my first love, I have a lot of time for crustaceans, and there’s usually a shrimp or crab of some kind that I’m hunting for during a trip.  At the heart of the Coral Triangle, I knew that the Bird’s Head’s high biodiversity would make it a great place to seek my latest target, the giant clam shrimp.  So, on my recent trip aboard Dewi Nusantara, I spent many hours scouring these massive molluscs for their miniscule residents, leading me to ponder the region’s other crustaceans too.


Coleman's shrimps from Raja AmpatCoral reefs are well known for the huge numbers of species they accommodate.  One of the reasons the biodiversity of a reef is so high are the close interrelationships between different species.  Most are very closely associated with just one species. Spotted and spiny porcelain crabs for example live only with certain anemones, Coleman’s shrimps live only with fire urchins, whip coral shrimps obviously live on sea whips and new examples are discovered all the time.  A few years ago, Ned and Anna DeLoach continued their legacy of discovery by finding a type of porcelain crab that lives only on the anemones that live on the shells of certain hermit crabs!  This level of union blows my mind, but is commonplace in Raja Ampat and the Coral Triangle.

Not Forgotten

When we talk about crustaceans, we automatically think of shrimps and crabs, but the group is in fact much larger, with many of the less well-known groups often going unnoticed.  For example, the isopods that stick to and feed on the blood of hapless fishes are a kind of crustacean.  One, the tongue-biter cymathoid isopod, lives in a fish’s mouth killing off its tongue and drinking its blood.

Four whip coral shrimpsDuring my most recent trip in Raja Ampat, unusually strong winds from the south prevented us from getting to a few of the sites we usually visit; however, it gave us opportunity to explore some rarely visited northern locations.  We headed to a small bay, not many miles south of the equator.  Here, as soon as we descended, there were great clouds of colonial pelagic tunicates, or salps.  This is unusual in itself, but these salps were accommodating an even more interesting companion.

Sea sapphires are yet another kind of copepod crustacean.  They’re often mistaken for falling fish scales in the blue water, but this iridescent shimmering is actually light reflected from the crystalline structures on their backs.  Only the males have this reflective surface, which is used to attract females that live inside the salps.  With so many salps in the area, there were a huge number of these sea sapphires too.  I found one that had a female and half a dozen male sea sapphires clustered within.  Since the males are usually free-swimming they had almost certainly entered the salp to mate.

Unusual Sightings

Cardinalfish with copepod parasiteRaja Ampat is so rich in terms of its marine life that it’s unsurprising to come across very rare and unusual crustaceans.  Over the years I’ve found harlequin and tiger shrimps, rarely seen cryptic sponge shrimps and thorny crinoid crabs amongst many others.  Recently my hunt for the giant clam shrimp was very fruitful and I saw quite a few of these scarcely photographed shrimps all around the region.  Obviously living in close association with giant clams, they are not at all easy to photograph.  Not only are they skittish and elusive, but their clam home is so sensitive to any localised water movement that is takes a great deal of patience and perseverance to find them.

These weren’t the only shrimps that I saw for the first time on this trip.  Another, the leopard anemone shrimp, is one that I’ve been hunting for years. As their name suggests, they live only on leopard anemones.  Stunning in their own right, these small colonial anemones are just a few centimetres in length themselves, so their tiny and amazingly well camouflaged shrimps are extraordinarily hard to find.  Thinking to myself, “Wouldn’t it be lovely if this anemone had one of those shrimps”.  I was shocked when it actually did.  Well, initially shocked but then I remembered I was in Raja Ampat where anything goes.

Links to Previous Blogs:

PART ONE | In Appreciation of Damsels

PART THREE |Sinister Hitchhikers

PART FOUR | The Pygmy Seahorses of Raja Ampat

PART FIVE | Raja Rarities

By Dr Richard Smith | Originally written for Science & Conservation Blog

BIOGRAPHY: Richard Smith, a British underwater photographer and writer, aspires to promote an appreciation for the ocean’s inhabitants and raise awareness of marine conservation issues through his images.  A marine biologist by training, Richard’s pioneering research on the biology and conservation of pygmy seahorses, led to the first PhD on these enigmatic fishes.  Over the past decade, Richard’s photographs and marine life focused features have appeared in a wide variety of publications around the world. Richard leads expeditions where the aim is for participants to get more from their diving and photography by learning about the marine environment through marine biology lectures: |

Bird’s Head Seascape – Natural History Notes (PT 1: In Appreciation of Damsels)

Bird’s Head Seascape – Natural History Notes (PT 1: In Appreciation of Damsels)

Damselfishes are a ubiquitous, but often overlooked, member of the Indo-Pacific reef fish community.  Around two hundred and fifty species, three quarters of the world’s damsels, are known to live in the Indo-West Pacific.  With the world’s highest marine biodiversity, where better to enjoy these fishes first hand than Raja Ampat?

Spawning blue green chromisDamselfishes are egg layers, most often laying their clutch on a pre-prepared nest site somewhere on the reef.  When their eggs hatch, the majority of species’ fry will immediately be swept off in the currents to disperse around the ocean.  Whilst the parents of these young fishes will never see the fruits of their reproductive endeavours, others raise young that never seem to leave home: the ‘Gen Y’ of the fish world. Over the past eleven days, I have been exploring the northern islands of Raja Ampat aboard Dewi Nusantara observing this unassuming group of fishes and their array of reproductive strategies.

Ecosystem Engineers

Many of us have had personal experience of a damselfish protecting its eggs.  Sergeant Majors, anemonefishes and golden damsels are amongst a few of the common damsels that will not hesitate to take on us bubble blowers, seemingly unperturbed by our comparatively massive size.  These demersal spawners, lay their eggs directly onto the substrate.  Sergeant Majors nest en masse, with dozens of individuals making a wasteland of a few square metres of the reef, laying their purplish spawn that they enthusiastically protect from marauders.  As such they are a kind of ecosystem engineer, altering the habitat for their own benefit but changing it for others too.

Spiny Chromis parent with frySpiny Chromis parent with frySwimming along a reef in northern Batanta Island, I came across a honeyhead damsel that had also strikingly altered its local environment.  Rather than denuding it to lay its eggs, it had encouraged verdant algal growth within the square metre or so of its territory that it enthusiastically warded me away from.  Like a disgruntled farmer it chased off any other creatures that tried to enter the confines of its little farmyard.  Within the allotment honeyheads farm filamentous algae, which act as their primary food source. Their agricultural proclivities, and the exclusion of other herbivores and corallivores, alter the composition of species within these plots.  By changing patches of the reef, these damsels are altering it for other species too. Their influences having a disproportionately large reach given their size.

Golden damsels on the other hand, usually lay their clutch of bright pink eggs on a whip coral or some other such protuberance coming off the reef.  You’ll often see the diligent parent tending to their clutch.  By aerating and removing infertile or spoiled eggs, they remove a reservoir of infection for others in the clutch.  Like the eggs of many fishes, the initially vivid fresh eggs soon become grey in colour as they mature and the fry develop within.  Just prior to hatching you can even see the reflective eyes of the tiny fish within.

Doting Parents

Juvenile spiny chromisOne of the more extreme parental investments of a damselfish is found in spiny chromis.  These inconspicuous damsels lay few large eggs, which both parents tend for an extended period until the relatively large fry hatch.  They are rare amongst reef fishes, in that the fry lack a pelagic larval stage and remain close to where they were born their entire life.  Although adults aren’t as protective of their fry as some other damsels, they keep an ever-watchful eye over the brood from hatching until they are quite large in size.  When small the fry are almost transparent, but take on a faint yellow stripe as they grow.  Adult spiny chromis have quite pointed fins and although variable in colour geographically, they are more often than not dark in colour, especially in the West Papua region.  Finally the youngsters darken to become miniature versions of their parents, and even at this late stage remain in a loose school casually overseen by their parents.

Changing Colours

A final quirk of damselfish reproduction, which for me makes them one of the most beautiful reef fish groups, is the diversity of their juvenile forms.  Adult black damsels, for instance, are midnight black in colour whereas their juveniles are almost indistinguishable as the same species.  They are unexpectedly white and bright yellow, with bluey black ventral and anal fins.  The leading theory for the dramatic change in colour or pattern from juvenile to adult in reef fishes is to reduce territorial aggression from adults.  If juveniles appear completely different, the adults are less likely to hound them out of their territory and the two can coexist amicably.

Damselfishes are a group that many divers seem to overlook.  I hope that I’ve convinced you to spare these unassuming fishes a thought on your next visit to the Bird’s Head. The more you learn about these abundant fishes the more fascinating they become, adding both to the diversity of the region and your diving experience.

Links to Previous Blogs:

PART TWO | Craving Cryptic Crustaceans

PART THREE |Sinister Hitchhikers

PART FOUR | The Pygmy Seahorses of Raja Ampat

PART FIVE | Raja Rarities

By Dr Richard Smith Originally written for Science & Conservation Blog

BIOGRAPHY: Richard Smith, a British underwater photographer and writer, aspires to promote an appreciation for the ocean’s inhabitants and raise awareness of marine conservation issues through his images.  A marine biologist by training, Richard’s pioneering research on the biology and conservation of pygmy seahorses, led to the first PhD on these enigmatic fishes.  Over the past decade, Richard’s photographs and marine life focused features have appeared in a wide variety of publications around the world. Richard leads expeditions where the aim is for participants to get more from their diving and photography by learning about the marine environment through marine biology lectures: |

Ocean Realm Images FLOW – Newsletter 2015

Ocean Realm Images FLOW – Newsletter 2015

I really don’t know what happened to 2015, but what a great years it’s been! There have been lots of amazing expeditions, creatures and publications to my name.  I hope you’ve all had a brilliant 2015 and looking forward to 2016 and beyond.  Here’s is a little run down of what I’ve been up to over the past 6 months:

Completed Trips

Leopard anemone shrimpApart from some non-group expeditions, in the six months since my last blog I’ve run trips to Atlantis Dumaguete Resort and aboard Atlantis’ Azores liveaboard around Cebu Island in the Philippines.  Most of the guests joined us for the entire 18 days and we saw such amazing creatures as 18 seahorses on one dive, 11 frogfishes on another, thresher sharks, whale sharks, Lembeh seadragons (Kyonemichthys rumengani) plus many more.  As always, we donated some of the proceeds from the trip to a conservation organisation.  In this case we chose the Marine Megafauna Foundation, who strive to protect the world’s biggest marine fishes.

Lynne's pipefishJust recently also I completed a trip aboard the Bilikiki in the Solomon Islands.  I am always blown away by the remoteness of the Solomons. The reefs are pristine and full of life, whilst on land, we went to a village that had never been visited by foreigners in the 60 years since it was founded.  I can’t imagine that’s true of many places in the world these days.  My underwater highlight was certainly Lynne’s pipefish (Festucalex rufus), which I have been looking for for sometime but had never seen before.


Upcoming Trips

I have recently added four brand new expeditions to the 2018 roster.  I know this seems terribly far away, but time flies! Our 2016 is basically full and 2017 is going the same way, so we figured it was time.  There are more details about trips below, alternatively keep an eye on my website, which I keep up to date:

2016 | I’ve been very fortunate with my trips filling up very quickly and there are only a couple of spots remaining to join my expeditions in 2016.  These last spaces are on the trip I’m leading for Dive Worldwide to Atmosphere Resort, Dumaguete in the Philippines.  To read more about this expert led ‘Dumaguete Dive Festival‘ please follow the link above or contact


2-12th March 2017 (10 nights) | All of Raja Ampat, West Papua, Indonesia.  Indo-Siren Liveaboard. ‘Four Kings Expedition‘ as an expert led group tour for Dive Worldwide.  For more information please follow the link
above or contact

23rd June – 3rd July 2017 (10 nights) | Underwater Photography Workshop at Siladen Resort, North Sulawesi, Indonesia. For more information please follow the link above or contact

Giant clam dottybackNEW | 22 – 31st August 2017 (9 nights) | Muck Magic Trip 1 – Sangeang Island & Bima Bay aboard Damai II (Labuan Bajo to Bima).  This ‘Our Beloved Seas’ trip is a joint trip between Wendy Brown and myself.  We have recently added this and the trip directly following it, but the second trip filled in minutes! If you’d like to join us in these exceedingly rich and rarely visited areas for critter hunting please contact Wendy or myself( for more information. We expect space to fill fast.



Hammerhead sharks in Galapagos IslandsNEW | Galapagos Islands aboard Galapagos Sky

25th February – 4th March 2018 (7 nights) | Trip 1

4-11th March 2018 (7 nights) | Trip 2

Wendy and I have repeatedly been asked by our guests to plan some trips to destinations outside the Coral Triangle. However, knowing how our regular guests love that area’s warm waters we have planned back to back trips to the Galapagos Islands in February/March when the waters of these mystical and historic islands tends to be warmer and clearer – whilst maintaining their renowned bounty.  As always, I’ll be giving talks and this will be the perfect place to share my passion for evolutionary biology, which was the subject of my Master’s degree.

NEW | 23rd July – 1st August 2018 (9 nights) | North Cenderawasih Bay & Mapia Island aboard Dewi Nusantara(Manokwari to Manokwari).  This first trip aboard Dewi Nusantara will take us to new ground.  Whilst we will start and end the trip in Cenderawasih Bay, we will take this opportunity to visit Mapia and its surrounding islands 100NM north of the bay, and the equator.  Here the remote and very rarely visited reefs are bustling with life and ripe to be explored.

NEW | 3 – 13th August 2018 (10 nights) | Classic Cenderawasih Bay aboard Dewi Nusantara (Manokwari to Sorong).  Starting in Manokwari, we will sail to the southern reaches of the bay in search of the area’s world renowned whale sharks.  We plan to spend a couple of mornings face to face with the sharks before continuing our search for other amazing fishes found only in the bay.  It is well know for the high numbers of endemics, which you’ll learn all about in my talks!



Sport Diving coverI haven’t only been underwater since my last update; I’ve been busy writing too.  I’ve continued with my regular series in both American and British Sport Diver Magazines, with ‘Get More from your Diving: Critter Hunting’ and ‘Species’ respectively.  I’ve also written the following stand-alone features:

‘Titillating Twilight – The Lure of North Sulawesi’ – Asian Diver

‘A Japanese Spin on the Night Dive – Hot Ke Night’ – Asian Diver

‘Changing Seas: Evolution in the Ocean’ – Scuba Diver AustralAsia

‘Solomon Islands: Reefs at the Edge of the World’ – Scuba Diver – Ocean Planet

‘Shooting for Science’ – Scuba Diver – Ocean Planet

‘Diving Mini Breaks: Australia’ – Sport Diving

‘Diving Mini Breaks: South Pacific’ – Sport Diving

‘Bird’s Head Natural History Notes part 1: In Appreciation of Damsels’ – Bird’s Head Seascape website. A new series about my adventures in the BHS.

Asian Diver coverI’ve also had a couple of cover shots for Asian Diver and Sport Diving magazines as well as having my shot ‘Whip Gobies and Eggs’ judged as a finalist in the ANZANG Nature Photographer of the Year.

Thinking ahead, I will also be speaking at the ADEX dive show in Singapore from 15-17 April 2016, so come along if you can!



Five Favourite Firsts of 2015

– I am always on the hunt for new and exciting beasties under the sea, so I thought as a final whimsy I would share my top five new finds of 2015.  After 3,000 plus dives there’s still so much to see.  This is why I keep diving and we always donate what we can to help preserve the amazing oceans.

1. Leopard Anemone Shrimp (Izucaris masudai) – Raja Ampat

2. Giant Clam Shrimps (Anchistus demani and Conchodytes tridacnae) – Wakatobi Dive Resort & Raja Ampat

3. Lynne’s Pipefish (Festucalex rufus) – Solomon Islands

Red Sea Longnose Filefish4. Red Sea Longnose Filefish (Oxymonacanthus halli) – Egyptian Red Sea

5. John Dory (Zeus faber) – Izu Peninsula, Japan

Finally, if you’d like to hear what I’m up to on a more regular basis, I suggest you check out my FaceBook page |





Ocean Realm Images FLOW – Newsletter June 2015

Ocean Realm Images FLOW – Newsletter June 2015


An update is long overdue but I’ve fallen sadly behind on blogs of my travels, publications and exciting marine life finds of late.  There’s a lot to catch up on here at Ocean Realm Images!

Guests on our Alor charter of Dewi NusantaraCompleted Trips

Since my last blog, I’ve completed several more successful trips as group leader; both alone and with Wendy Brown as ‘Our Beloved Seas’ trips.  The trips have included Tubbataha and Dumaguete in the PhilippinesAlor, Wetar and Wakatobi in Indonesia and most recently Northern Raja Ampat (follow links above to galleries and trip reports).  We saw some amazing marine life living where it shouldn’t (The thinline wobbegong shark (Orectolobus leptolineatus) in Alor and the mimic jawfish (Stalix sp) in Dumaguete) and several firsts for me – including species for which very few sightings have ever occurred (Humann’s fairy wrasse (Cirrhilabrus humanni), new species of flasher wrasse in Alor (Paracheilinus sp.), soft coral pipefish (Siokunichthys breviceps) and harlequin grouper (Cephalopholis polleni)).

Cross's Damselfish juvenileConservation

Wendy and I are very pleased that so far from our three trips, we’ve been able to pass some of the proceeds to conservation efforts specific to the regions we’ve visited.  So far we’ve donated $1500 to help the amazing work of the conservation charities Save Our Seas Foundation and Conservation International.  We both think it’s hugely important that we give something back to preserve the oceans that we love so much.  We hope you agree!

Future Expeditions

There are lots of exciting expeditions in the pipeline too. I have a number of charters coming up this year and all the way through to 2017 (I’ve even started plotting 2018!).  We can still accommodate a few people on trips this year; including the land portion of a trip to Atlantis Dumaguete Resort in the Philippines and in the Solomons too, so do contact me if you’re interested.  Follow the links below for more details or check out my expeditions page here

Richard giving a talk in London for Dive WorldwideI have also started a new and exciting venture with Dive Worldwide, a UK based diving company for whom I will start leading trips as of February 2016.  I recently gave a talk about our upcoming Philippines trip at London’s Russell Square Hotel.  The talk went very well, and it was apparently the best attendance they’ve had.  It was great to meet some of the folk who have already signed up and those who since have.  Keep your eyes peeled on my social media (Facebook and Twitter) for details of my next talk with them, which is currently in the planning stage.



Upcoming trips (with spaces):

12-21st September 2015 | Philippines | Land-based stay at Atlantis Dumaguete Resort.

12-22nd December 2015 | Solomon Islands | Live-aboard trip on Bilikiki.

21st February – 2nd March 2016 | Philippines | Trip with Dive Worldwide to Atmosphere Resort, Dumaguete.

18-29th March 2017 | Indonesia | Trip to Triton Bay aboard Dewi Nusantara. Only one cabin remaining.

Richard's Sport Diving cover shot of diver and whale sharkPublications

I’ve been extremely busy writing for various publications around the world.  Since my last update, I have begun writing a regular monthly column for Sport Diver magazine in the US, called ‘Species’, which has so far covered: Crinoids, Goliath Groupers, Caribbean Spiny Lobster, Sea Stars and Whale Sharks.  I also completed my five part series in British Sport Diver magazine ‘Photographing Behaviour’, and have now begun a new series ‘Critter Hunting’.  I’ve also had a series ‘Mini Breaks’ in Sport Diving magazine and a couple of cover shots with them too.  In addition to those regular features, I’ve also had pieces in Wild Travel magazine, Action Asia, Depth Magazine, Aquanaut, Silent World, X-Ray magazine, Diver, Dive!  I’ve been busy to say the least!

Ocean Realm Images…and Films

Finally, if you like moving images, I have recently started shooting HD video with my D800 SLR camera.  The first video that I’ve put together is now up on my YouTube channel ‘Diving The World’s Richest Reefs – Raja Ampat, Indonesia‘.  Check out the link and I hope you enjoy it.

Scientific Publication on Pygmy Seahorse Habitat Specialisation and Population Structure

Scientific Publication on Pygmy Seahorse Habitat Specialisation and Population Structure

My scientific publication on the habitat specialisation and population structure of gorgonian-associated pygmy seahorses has just been published in the journal Marine Ecology Progress Series (Link to the MEPS page):


Smith RE, Grutter AS & Tibbetts IR (2012).  Extreme habitat specialisation and population structure of two gorgonian-associated pygmy seahorses.  Marine Ecology Progress Series 444: 195-206


The study was conducted on the two species of pygmy seahorse, Bargibant’s (Hippocampus bargibanti) and Denise’s species (H. denise), which require a living gorgonian coral for their survival.  The main findings of my study are below in the paper’s abstract but I’ve also written some of the study’s important findings below.

– Bargibant’s (Hippocampus bargibanti) and Denise’s pygmy seahorses (H. denise) have some of the lowest densities of any unexploited seahorse populations studied thus far.
– Bargibant’s pygmy seahorse is an extreme habitat specialist, being found exclusively in association with a single genus of gorgonian coral, Muricella spp.
– Denise’s pygmy is a relative generalist as it is found in association with at least eight genera of gorgonian corals.
– It is possible to distinguish between male and female pygmy seahorses by examining the area at the base of the abdomen where males have a small slit-like opening to the brood pouch (figure b) and females have a raised, circular urinogential pore (figure a) (see image).


Sex discrimination in pygmy seahorses